Forming operations are traditionally divided into machining (mass removal, milling, lathing, drilling, and chip production, waste) and deformation (mass conserving, forging, pressing, and rolling at low temperature, and molding at high temperature). For nanometer scaling forming, options have been comparatively limited. Generally, these must be mass preserving and involve unusual geometries. The increased role of surfaces and constitutive behavior may also be altered.
The replication of high resolution shapes patterned into a master silicon or quartz stamp on a target polymer film surface by direct mechanical contact is a new and promising low cost nanofabrication and microfabrication technique. Known generally as “nanoimprint”, the technique has been demonstrated in applications such as semiconductor lithography, nanoelectronics, microelectronics, polymer electronics, microfluidics (lab-on-a-chip), and biological materials patterning.
Nanoprint techniques typically involve either a liquid molding process or specialized precursor materials that are subject to radiation based crosslinking to realize a permanent solid structure, or hot embossing of thermally softened films which are then quenched to solid state before demolding occurs. Limited work has been performed on purely mechanical imprinting in which shear stresses generated under normal load are sufficient to induce plastic flow.
Forming materials by direct mechanical means can be divided between machining or material removal processes and deformation which involves mass preserving forging and molding processes. Direct mechanical techniques can be used on a larger variety of substances, but these techniques are subject to a number of fidelity limiting issues including ultrahigh extrusion aspect ratios, strain hardening, and elastic relaxations of the bounding surfaces due to the large pressures involved. Nanoindentation is a type of contact mechanics where the response to applied force is divided into elastic and plastic permanent indent produced). One must know tip shape to convert force and displacement to materails parameters. It is also difficult to use at 2-3 nm, although it works well at greater than 4 to 5 nm. Nano-imprint lithography or contract printing has a number of advantages, including reduced cost, simple rapid process, wide choice of materials, and high resolution. However, there are still issues with stability and fidelity of form patters, de-molding and variation of temperature, and multi-layer or multi-step processing.
Thus, there is a need for improved systems and methods for producing micro- and/or nanostructures using direct mechanical techniques.
It is therefore an object of the present invention to provide systems and methods for producing micro- and/or nanostructures using direct mechanical techniques that overcome problems such as extrusion aspect ratios far from unity, that exhibit strain hardening, and that suffer elastic relaxation of the bounding surfaces.